JP5238828B2 - Manufacturing method of optical film - Google Patents

Description

  The present invention relates to a turret type film winding apparatus and a film manufacturing method using the apparatus, and more particularly to an apparatus improvement when an air press system is applied to a turret type film winding apparatus.

  For example, a protective film that uses a film of triacetyl cellulose (TAC) or the like formed itself to protect a polarizing plate of a liquid crystal display device, or a process that is applied to the formed film, such as coating and drying. Optical films such as optical compensation films and antireflection films are required to have a high level of surface performance.

  The film is generally formed by a solution film forming method or a melt film forming method, and the formed film is wound on a winding device. Therefore, winding such as winding misalignment, winding curl, scratches (including micro scratches of about 50μ to 100μ) at the time of winding, bevel deformation at the center of the film, deformation at the end of the film (commonly known as an ear) (bevel or depression) Failure is a major quality issue.

  Since a winding failure in a film leads to a subsequent coating failure or drying failure, a user is subjected to a stricter inspection than a product film. In particular, due to the recent widening of the film (for example, 2000 mm or more), it is difficult for the air to escape during winding, so that it is difficult to wind without causing a winding failure.

  In general, when winding a traveling film around a winding shaft to form a winding roll, the entrained air accompanying the traveling of the film is caught between the film layers, so that the winding becomes loose and winding misalignment, etc. Winding failure occurs. The above-described bevel or depression is a phenomenon in which the entrained air caught in the winding roll at the time of winding escapes from the winding roll with the passage of time, and the removed portion buckles. Therefore, in order to obtain a winding hardness that does not cause winding deviation, it is necessary to exclude entrained air during winding. In particular, as the film width increases as in recent years, the entrained air that has been entrapped in the winding roll during winding is less likely to escape from both ends of the winding roll, so that a winding failure tends to occur.

  A conventional general winding method for excluding entrained air is a method of increasing the winding tension. However, in the method of increasing the winding tension, the air entrainment (especially in the central part in the film width direction) is low, and the ear part deformation (beveling or stretching of the knurling part) is caused by stress concentration on the ear part in the film width direction. There are disadvantages that occur.

  In view of this, a winding device that can eliminate entrained air without increasing the winding tension has been developed.

  The winding apparatus of patent document 1 is excluding the entrainment air wound in a winding roll by winding up the winding roll surface of a winding start point by air press with a press roller.

  However, the winding device of Patent Document 1 cannot prevent the occurrence of a scratch due to slip or the like because the pressing roller contacts the film surface. In particular, if foreign matter such as dust adheres to the surface of the winding roller, large scratches are likely to occur due to foreign matter interposed between the pressing roller and the winding roll.

  Therefore, in particular, as a winding device for an optical film, for example, a winding device of, for example, Patent Document 2 of an air press type that does not contact the surface of a winding roll is often employed.

  The winding device of Patent Document 2 can exclude entrained air that is caught in the winding roll in a non-contact state with the winding roll by blowing air from the air nozzle onto the surface of the winding roll.

JP 2002-220143 A JP 2005-096915 A

  By the way, in the case of adopting an air press system in a turret type winding device that has a plurality of winding shafts and continuously performs film winding without stopping the line, as shown in FIG. It is necessary to move the winding roll 1 in the fully wound state of the final winding stage from the winding position and then move the winding shaft 2 to be wound to the winding position. For this reason, it is necessary to turn the turret 3 180 degrees around the turning shaft 3A. In this case, the air nozzle 4 becomes an obstacle during the turning of the turret 3, and there arises a problem that the air nozzle 4 has to be temporarily retracted outside the turning track 5 of the turret 3. Here, the turning trajectory of the turret 3 means a locus (one-dot chain line) drawn by the outermost edge of the winding roll 1 having the longest distance from the center O of the turning shaft 3A of the turret, as shown in FIG.

  By retracting the air nozzle 4, air press on the surface of the winding roll 1 is not performed when winding the outer periphery of the winding roll 1, which is the final stage of winding. Will occur. Conventionally, this has been done by increasing the winding tension when winding on the outer peripheral side.

  However, even if the winding tension is increased at the time of winding on the outer peripheral side, the winding failure cannot be solved. In particular, in the case of a wide film having a film width of 2000 mm or more, the entrained air cannot be sufficiently removed, so that a winding failure such as a bevel or depression occurs. Further, even when the film width is 2000 m or less, winding misalignment failures that occur at the timing when the winding tension is increased frequently occur.

  The present invention has been made in view of such circumstances, and even when the air press method is applied to the turret type film winding device, it is not necessary to retract the air nozzle when the turret is turned, Since it is possible to perform air press on the winding roll from the start to the end, the entrained air can be efficiently removed and the film winding device is optimal for winding a film that requires a high level of surface performance. And it aims at providing the manufacturing method of the film using this apparatus.

In order to achieve the above object, the method for producing an optical film according to claim 1 includes a film winding process for winding the optical film with a winding device, and the winding device winds a belt-shaped film that travels. 3800 m or more is wound to form a winding roll, and a fully wound winding roll is moved from the winding position by turning a turret provided with a plurality of winding shafts around the turning shaft. A turret type device that moves a winding shaft that is wound around a winding position to the winding position, wherein an air nozzle that blows air with a pressure of 5 to 30 kPa on the surface of the winding roll and presses the hollow shaft While maintaining a predetermined distance between the air introduction line for introducing air into the air nozzle via the pivot shaft and the air nozzle outlet and the winding roll surface. A moving means for moving the air nozzle following the change in the winding diameter of the winding roll, and an air ejection unit provided at least for each winding shaft and integrally provided with the turret. It is comprised so that it may turn together with turning of the turret.

  Here, introducing air into the air nozzle via the swivel shaft includes not only using the swivel shaft itself as an air press pipe but also providing an air hose in the swivel shaft.

According to the method for producing an optical film of the present invention, since the winding process of the optical film is performed by the film winding apparatus described above, winding misalignment, curl, and scratches at the time of winding (a fineness of about 50 μ to 100 μ) No winding failures such as scratches), bevel deformation at the center of the film, deformation of the film end (commonly referred to as the ear) (knurling bevel or elongation), etc. Thereby, a planar high quality optical film can be manufactured.

  Therefore, even when the air press method is applied to the turret type film winding device, it is not necessary to retract the air nozzle when the turret is turned, and the winding from the start to the end of the winding on the winding shaft is not required. An air press to the rotating roll can be performed. Thereby, the winding failure resulting from accompanying air can be prevented effectively.

  According to the present invention, it is preferable that the air ejection unit is disposed in a turning trajectory of the turret. Thereby, when the turret turns, the air ejection unit does not come into contact with the devices arranged around the turret, and the apparatus can be made compact.

  According to the present invention, it is preferable that the rotary shaft is provided with a rotary joint that rotatably connects an air pipe to an air source provided outside the turret. Thereby, the air introduction line is not twisted by the turning of the turret.

  In the present invention, there is provided a guide roller for wrapping the film wound around the winding roller by turning together with the turret when the turret is turned, and the air is provided in the travel path of the film wrapped by the guide roller. It is preferable that the ejection unit is arranged.

  As a result, the guide roller can regulate the travel path of the film so that the film being wound does not come into contact with the air ejection unit when the turret rotates, so that the film comes into contact with the air ejection unit to the film. There will be no scratches.

  In this invention, it is preferable that the said moving means moves the said air nozzle, maintaining the distance of the blower outlet of the said air nozzle, and the said winding roll surface 2-15 mm. If it is less than 2 mm, the outlet of the air nozzle may come into contact with the surface of the winding roll, and if it exceeds 15 mm, the pressure for air-pressing the surface of the winding roll will be insufficient for reliably removing the accompanying air. Moreover, even if the winding diameter of a winding roll changes, a moving means can maintain the air press pressure to a winding roll surface uniformly with a suitable pressure.

  In the present invention, the air introduction line is branched from the pivot shaft to a header pipe provided for each air nozzle, and the air is supplied from the header pipe through a plurality of flexible hoses in the width direction of the air nozzle. It is preferable to introduce them evenly. Thereby, even if the air nozzle width increases corresponding to the film width to be wound, the surface of the winding roll can be evenly pressed in the width direction.

  In the present invention, it is preferable that each header pipe is provided with a switching means capable of switching the air from the swiveling shaft to each winding shaft air nozzle within 3 seconds. Thereby, switching of the air press to the surface of a winding roll can be rapidly performed according to the end of film rewinding between a plurality of winding shafts. Therefore, a winding failure due to the accompanying air does not occur during rewinding.

  In the present invention, it is preferable that a pair of the moving means is provided at both end positions in the air nozzle width direction so that dust of the driving unit does not fall on the film. This makes it difficult for dust generated from the drive unit of the moving means to adhere to the film. In particular, when the film is an optical film, the adhesion of foreign matter such as dust to the film affects the quality. Therefore, when the air ejection unit is provided integrally with the turret, it is generated from the drive unit of the moving means. It is important to prevent dust from adhering to the winding roll. A drive part is a ball screw or a linear guide, for example.

In the present invention, it is preferable that a cover is provided on the driving unit of the moving means.
Thereby, it can prevent reliably that the dust which generate | occur | produces from the drive part of a moving means is scattered outside.

  In the present invention, the width of the film is preferably 2000 mm or more.

  When the film width is 2000 mm or more, it becomes difficult to escape from both ends of the winding roll when entrained air during winding is taken into the winding roll. Therefore, the present invention is particularly effective when the film width is 2000 mm or more. Even when the width of the film is 2000 m or less, it is effective for preventing winding deviation.

  As the film forming step, for example, a solution film forming method in which a dope in which a raw material resin is dissolved or dispersed in a solvent is cast into a thin film on a support, or a molten resin obtained by melting the raw material resin with an extruder is cooled from a die. A melt film-forming method that extrudes in a thin film on a drum can be employed.

  According to the present invention, since the film winding process is performed by the above-described film winding apparatus, winding misalignment, winding wrinkles, scratches (including micro scratches of about 50 μ to 100 μ) at the time of winding, and the center of the film No winding failure such as deformation of the tape and deformation of the film edge (common name, ear) (knurling or stretching) occurs. Thereby, since a coating failure and a drying failure due to a winding failure do not occur in the coating step and the drying step, a high-quality optical film can be manufactured.

  In this invention, it is preferable to provide the product film winding process which winds up the said manufactured optical film with the film winding apparatus of any one of Claims 1-10.

  Even when the optical film of the product is wound, if the film winding apparatus of the present invention is used, a higher quality optical film can be produced.

  In the present invention, the optical film is preferably any one of a polarizing plate protective film, an optical compensation film, and an antireflection film of a liquid crystal display device. This is because such an optical film is required to have extremely high surface performance.

  According to the film winding device of the present invention, even when the air press method is applied to the turret type winding device, it is not necessary to retract the air nozzle when turning the turret, and the winding is performed from the start to the end of the winding. Since the air press to the roll can be performed, high quality can be ensured with the entire winding length.

  Therefore, according to the method for producing an optical film using this winding device, an optical film that requires high planar performance can be produced.

Schematic diagram incorporating the film winding device of the present invention into a film production line The perspective view of the turret type film winding device of the present invention Side view of turret type film winding apparatus of the present invention Explanatory drawing of the moving means which moves the air nozzle of the turret type film winding apparatus of this invention Explanatory drawing explaining the effect | action of the turret type film winding apparatus of this invention Side view of another embodiment of the turret type film winding apparatus of the present invention Conceptual diagram of incorporating the turret type film winding device of the present invention into an optical compensation film production line Explanatory drawing explaining the Example of the turret type film winding apparatus of this invention Explanatory drawing explaining the Example of the conventional turret type film winding apparatus

  Hereinafter, a preferred embodiment of a film winding apparatus of the present invention and a method for producing an optical film using the apparatus will be described in detail.

  FIG. 1 is a conceptual diagram in which a turret type film winding device 10 of the present invention is incorporated in a film forming line 14 for a film 12.

  As shown in FIG. 1, the film 12 manufactured by the film forming line 14 is wound up by a turret type film winding device 10 via a film winding device 16. In the present embodiment, an example of a biaxial turret type film winding apparatus having two winding axes will be described, but two or more axes may be used. As the film forming line 14, for example, a solution film forming method in which a dope obtained by dissolving or dispersing a raw material resin in a solvent is cast into a thin film on a support, or a molten resin obtained by melting a raw material resin with an extruder is removed from a die. A melt film-forming method that extrudes in a thin film on a cooling drum can be employed.

  Also, the film rewinding device 16 winds the film 12 when one of the two shafts is fully wound and the turret turns and an empty winding shaft is positioned at the winding position. Is a device for switching from a fully wound winding shaft to an empty winding shaft. A detailed description of the film rewinding device 16 is omitted because it is not the gist of the present invention, but for example, a film rewinding device described in Japanese Patent Application Laid-Open No. 2008-230723 can be suitably used.

  A winding drive control unit 10A that drives and controls winding of the film winding device 10 and a winding drive control unit 16A that drives and controls winding of the film winding device 16 are controlled by commands from the controller 18.

  As shown in FIGS. 2 and 3, the biaxial turret type film winding device 10 mainly includes a turret 22 rotatably provided on a gantry 20, and an air ejection unit 24 that rotates together with the turret 22. , Composed of. 2 and 3, the posture of the turret 22 during film winding is inclined as compared with the horizontal state of FIG. 1, but the posture is not particularly limited.

  The gantry 20 is formed in a concave shape in cross section by a bottom plate 20A and a pair of side plates 20B and 20B arranged to face each other at a distance from the width of the film 12. Further, a turning shaft (rotating shaft) 26 is rotatably supported by a pair of bearings (not shown) provided at the upper ends of the pair of side plates 20B, 20B. The turret 22 is composed of a pair of arm plates 28, 28 that face each other in parallel, and the center of the pair of arm plates 28, 28 is supported by the turning shaft 26. The turning shaft 26 is connected to a rotational drive source (not shown). Thereby, the turret 22 is turned by turning the turning shaft 26. In the present embodiment, the turret 22 is described as an example of an arm-shaped turret, but a disk-shaped turret constituted by a pair of parallel disks may be used.

  Bosses 30, 30 protrude from the inner sides of both ends of the pair of arm plates 28, 28, and a hollow winding core 31 is fitted and supported on the pair of bosses 30, 30. Thereby, the winding shaft 32 which winds up the film 12 is formed. In addition, the winding shaft 32 which is in the winding position close to the film rewinding device 16 and is winding is referred to as a first winding shaft 32A. In addition, an empty winding shaft 32 waiting at a standby position far from the film rewinding device 16 for the next winding is referred to as a second winding shaft 32B.

  The winding drive control unit 10A drives and controls the intermittent rotation (180 degrees) of the turret 22 and the rotation of the winding shafts 32A and 32B based on commands from the controller 18.

  Further, a winding diameter sensor (not shown) that measures the winding diameter of the winding roll 34 wound around the first winding shaft 32A is provided in the vicinity of the winding position, and a detection signal is sent to the controller 18. . The controller 18 calculates the winding diameter of the winding roll 34 as needed from the detection signal of the winding diameter sensor, and outputs a rewinding command to the film winding device 10 and the film rewinding device 16 when the winding diameter becomes full.

  The air ejection unit 24 provided integrally with the turret 22 air-presses the surface of the winding roll 34 and prevents entrained air accompanying the film 12 to be wound from being caught in the winding roll 34. This is provided for each of the first and second winding shafts 32A and 32B. That is, the air ejection unit 24 blows air onto the surface of the winding roll 34 and air presses the air nozzle 36 and the swivel shaft 26 so as to be hollow, and introduces air to the air nozzle 36 via the swivel shaft 26. The air introduction line 38 and moving means 40 for moving the air nozzle 36 following the change in the winding diameter of the winding roll 34 are configured. The air ejection unit 24 is provided integrally with the turret 22 so as to turn together with the turning of the turret 22. The air ejection unit 24 configured as described above is preferably provided in the turning trajectory S of the turret 22. The turning trajectory S of the turret 22 refers to a trajectory (two-dot chain line) drawn by the outermost edge of the winding roll 34 having the longest distance from the center O of the turning shaft 26 of the turret 22 as shown in FIG.

  The air nozzle 36 has a slit-shaped air outlet 36 </ b> A formed to have a width equal to the width of the film 12, and air supplied from the air introduction line 38 is blown from the air outlet 36 </ b> A toward the surface of the winding roll 34. .

  The air introduction line 38 includes a plurality of flexible hoses 38B having one end connected to a plurality of air intake ports 38A formed in the width direction of the air nozzle 36, and a header to which the other ends of the plurality of flexible hoses 38B are connected. The pipe 38C and the hollow pivot 26 that communicates with the header pipe 38C are configured. And the air piping 42 to the air generator (not shown) of air is connected to rotary joint 38D provided in the turning shaft 26. Thereby, even if the air ejection unit 24 turns together with the turning of the turret 22, the air introduction line 38 is not twisted.

  A plurality of flexible hoses 38B and header pipes 38C are provided for each air nozzle 36, and an open / close valve (not shown) is provided in each header pipe 38C. Each open / close valve performs an open / close operation according to an instruction from the controller 18. That is, the opening / closing valve of the header pipe 38C for sending air to the air nozzle 36 during film winding is opened, and the opening / closing valve of the other header pipe 38C is closed.

  Thereby, the air from the air generator is supplied to the air nozzle 36 through the air pipe 42, the rotary joint 38D, the hollow turning shaft 26, the header pipe 38C in which the opening / closing valve is opened, and the plurality of flexible hoses 38B. The The pressure at which the surface of the winding roll 34 is air-pressed with air from the air nozzle 36 is preferably in the range of 5 to 30 kPa. If the pressure to press the air is less than 5 kPa, the effect of eliminating the entrained air is small, causing a winding failure, and if the pressure exceeds 30 kPa, the pressure of the air press is too strong and becomes too hard. There is a risk of belt winding failure.

  The moving means 40 moves the air nozzle 36 forward and backward relative to the surface of the winding roll 34 while maintaining a predetermined distance from the surface of the winding roll 34, and is configured as follows. That is, the pair of opposing arm plates 28, 28 are provided with extending plates 28A, 28A extending in opposite directions from both ends thereof, and the arm plate 28 is formed in an N shape. In addition, two linear guide rails 44 are laid in parallel to each other in the direction orthogonal to the axis of the first or second winding shaft 32A, 32B on the inner side of the opposing extension plates 28A, 28A. The Further, both ends of the air nozzle 36 are supported by the opposing rail 44 via a block 46 and a slide block (nut member) 48. A ball screw 50 is screwed onto the slide block 48, and one end of the ball screw 50 is connected to a rotating shaft of a motor 52 supported by the extending plate 28A.

  And the controller 18 controls the rotation speed of the motor 52 based on the winding diameter of the winding roll 34 calculated by the detection signal from a winding diameter sensor. 4A and 4B, the winding diameter of the winding roll 34 while maintaining the distance L between the air outlet 36A of the air nozzle 36 and the surface of the winding roll 34 at a predetermined distance. The air nozzle 36 can be moved following this change. 4A shows a state where the winding diameter is thin, and FIG. 4B shows a state where the winding diameter is thick.

  The distance L between the air outlet 36A of the air nozzle 36 and the surface of the winding roll 34 is preferably in the range of 2 mm to 15 mm. If it is less than 2 mm, the air outlet 36 </ b> A may come into contact with the surface of the winding roll 34, and if it exceeds 15 mm, the pressure for air pressing the surface of the winding roll 34 is insufficient to eliminate the accompanying air. Further, it is preferable that a dust cover (not shown) is provided on the linear guide (rail 44 and block 46) and the ball screw 50 to prevent dust generated from scattering.

  Further, as shown in FIG. 3, the turret 22 has a film 12 immediately before being taken up by the winding roll 34 when the turret 22 is swung, and the flexible hose 38 </ b> B of the air ejection unit 24, particularly the air introduction line 38. It is preferable to provide a guide roller 54 that regulates the travel path of the film 12 so as not to contact the moving means 40. That is, as shown in FIG. 3, the support arm 56 is extended from the extended plate 28A to the outside of the flexible hose 38B in a curved shape. A guide roller 54 is rotatably supported at the tip and center of the support arm 56. As a result, the guide roller 54 that wraps the film 12 that is turned together with the turret 22 and is wound around the winding roll 34 when the turret 22 is turned is provided, and in the travel path of the film 12 that is wrapped by the guide roller 54. Thus, a configuration in which the air ejection unit 24 is disposed is formed.

  The number of guide rollers 54 is not limited to two. In FIG. 3, the guide roller 54 is supported by the support arm 56 extending from the extending plate 28 </ b> A, but the supporting portion of the guide roller 54 is formed by adopting the disk-shaped turret described above. May be. In short, the guide roller 54 may be configured to rotate together with the rotation of the turret 22. Thereby, when the turret 22 turns, it is possible to prevent the film 12 immediately before being wound around the winding roll 34 from coming into contact with the air ejection unit 24, so that the surface of the film 12 is not damaged by the contact.

  Next, the operation of the film winding device 10 configured as described above will be described.

  As shown in FIG. 5A, at the winding position, the film 12 is wound around the first winding shaft 32A, and the surface of the winding roll 34 is air-pressed by the air blown from the air nozzle 36. This prevents entrainment air accompanying the traveling of the film 12 from being caught in the winding roll 34 and causing the above-described winding failure.

  Next, when the controller 18 detects that the winding diameter of the film 12 to be wound is full by a detection signal from a winding diameter sensor (not shown), the controller 18 sends a rewind command to the film winding device 10. It is sent to the take-up drive control unit 10A and the rewinding drive control unit 16A of the film rewinding device 16. For example, when the film 12 is wound on the first winding shaft 32A by 4000 m, the controller 18 determines that the winding is full at the winding diameter of 3800 m and issues a rewinding command.

  Based on the rewinding command, the winding drive control unit 10A turns the turret 22 by 180 degrees and turns the second winding shaft 32B located at the standby position to the winding position, as shown in FIG. Move to. On the other hand, the fully wound winding roll 34 moves to the standby position and continues to wind the film 12 until the film rewinding device 16 completes the rewinding of the film 12 (until 4000 m is wound).

  In such turning of the turret 22 for film rewinding, the air ejection unit 24 including the air nozzle 36 is provided integrally with the turret 22, and thus turns together with the turning of the turret 22. Accordingly, even when the air press method is applied to the turret type film winding device 10, it is not necessary to retract the air nozzle 36 out of the turning track S when the turret is turned. Therefore, the air press on the surface of the winding roll 34 can be continuously performed from the start to the end of film winding on the first winding shaft 32A. In particular, since the air pressing is performed on the surface of the winding roll 34 from the start to the end of the rewinding by turret rotation (between 3800 m and 4000 m), the conventional turret type winding device is used. Thus, a winding failure does not occur after the start of rewinding (that is, the outer periphery of the winding roll).

  Furthermore, in the embodiment of the present invention, since the guide roller 54 that rotates together with the turret 22 is provided, the film 12 immediately before being wound around the winding roll 34 comes into contact with the air ejection unit 24, and scratches, etc. There is no failure.

  This will be described with reference to FIG. 5. When the turret 22 turns 90 degrees from the state of FIG. 5A, the state of FIG. 5B is obtained. As can be seen from FIG. 5B, before the flexible hose 38B and the moving means 40 come into contact with the film 12 just before winding, the guide roller 54 wraps around the film 12 and rotates. Then, as shown in FIG. 5C, when the turret 22 turns 180 degrees, a travel route is formed so that the film 12 travels outside the flexible hose 38B and the moving means 40. Thereby, it is possible to prevent the film 12 immediately before being wound around the winding roll 34 when the turret 22 is turning from coming into contact with the air ejection unit 24.

  On the other hand, when the turret 22 turns and the second winding shaft 32B is moved to the winding position, the rewinding drive control unit 16A cuts the film 12 wound on the first winding shaft 32A, The front end portion of the cut film 12 is attached to the second winding shaft 32B. Simultaneously with the sticking, the winding drive control unit 10A rotates the second winding shaft 32B, and winding onto the second winding shaft 32B is started. Thereby, the traveling film 12 is wound from the first winding shaft 32A to the second winding shaft 32B, and the film 12 is continuously wound.

  At substantially the same time as the end of the rewinding, the controller 18 closes the opening / closing valve of the header tube 38C on the first winding shaft 32A side, and opens the header tube 32C on the second winding shaft 32B side. Thereby, air is blown from the air nozzle 36 onto the surface of the winding roll 34 wound around the second winding shaft 32B, and the accompanying air accompanying the film 12 is excluded.

  The timing for switching the on-off valve is preferably as early as possible, but preferably within 3 seconds from the end of rewinding, it is possible to prevent the occurrence of winding failure and there is no problem.

  Thus, according to the film winding device 10 of the present embodiment, even when the air press method is applied to the turret type winding device, it is not necessary to retract the air nozzle 36 when the turret is turned, and the winding is performed. Since the air press to the winding roll 34 can be performed from the start to the end of taking, the accompanying air can be efficiently eliminated. Thereby, a winding failure can be reliably prevented.

  In the film winding apparatus 10 described above, the air ejection unit 24 is arranged so as to perform air pressing by blowing air upward on the winding roll 34 being wound. However, as shown in FIG. 6, the air ejection unit 24 may be arranged so as to blow air laterally against the winding roll 34, and although not shown, it may be blown downward. In this way, by blowing air to the winding roll sideways or downward, the dust generated at the time of winding is less likely to rise, so that it is possible to prevent the dust from reattaching to the surface of the winding roll.

  In the film winding device 10 described above, the film formed is wound as it is, for example, in the case of winding when manufacturing a protective film for a polarizing plate, etc. Next, referring to FIG. An example of a manufacturing method for manufacturing an optical film by further applying coating and drying to the film 12 wound on the film winding device 10 will be described. An example of the optical compensation film will be described as an example of the optical film.

  In addition, the film winding device of the present invention is effective for winding when the above-described film itself is used as a protective film for a polarizing plate, as well as winding of an optical film provided with a functional coating solution. Of course, it is also effective for taking out.

  Here, an example of an optical compensation film will be described as an example of an optical film provided with a functional coating solution. However, the optical film is not limited to an optical compensation film, and is dried after a curable coating solution is applied on a belt-like film. The present invention can also be applied to methods for producing various optical films, for example, an antiglare film and an antireflection film, in which the coating layer is dried with heated air in the zone and the coating layer dried in the curing zone is cured.

  FIG. 7 is a schematic diagram showing the overall configuration of the optical compensation film manufacturing apparatus 100.

  As shown in FIG. 7, a belt-like film 12 on which a transparent resin layer for forming an alignment film is formed in advance is sent out from a turret type sending machine 112. Reference numeral 114 denotes a film bonding apparatus that automatically bonds the rear end portion of the film 12 of the old roll and the front end portion of the film 12 of the new roll.

  The film 12 delivered from the delivery device 112 via the film joining device 114 is sent to the rubbing processing device 118 disposed on the downstream side while being guided by the guide roller 116, and the rubbing roller 120 rubs the transparent resin layer. The Thereby, an alignment film is formed.

  In the rubbing processing device 118, the rubbing roller 120 is disposed between two transport rolls in the continuous transport process of the film 12. Then, the film 12 is continuously rubbed by being wrapped and conveyed by a rotating rubbing roller 120. In this case, the rubbing roller 120 may be arranged such that its rotation axis is inclined with respect to the transport direction of the film 12.

  A dust remover 122 is disposed on the downstream side of the rubbing processing device 118 to remove dust adhering to the surface of the film 12. Further, a gravure coating device 124 is disposed on the downstream side of the dust remover 122, and a coating liquid containing a liquid crystalline compound is applied on the alignment film of the film 12. As the liquid crystal compound, a liquid crystal discotic compound having a crosslinkable functional group is preferably used.

The gravure coating device 124 includes a gravure roller 126 and a liquid receiving pan 128 disposed below the gravure roller 126 and filled with a coating liquid containing a liquid crystal compound. Is immersed in a coating solution. Further, a blade 129 is disposed at about 10 o'clock position of the gravure roller 126. As a result, the coating liquid is supplied to the cells on the surface of the gravure roller 126, and the excess coating liquid is scraped off by the blade 129 and then applied to the alignment film surface of the film 12. The coating amount of the coating solution is preferably 10 mL / m ² or less.

  The upstream guide roller 117 and the downstream guide roller 119 are arranged in a state substantially parallel to the gravure roller 126. Further, it is preferable that the upstream guide roller 117 and the downstream guide roller 119 are rotatably supported at both ends by a bearing member (such as a ball bearing) (not shown) and do not have a drive mechanism. The gravure coating device 124 is preferably provided in a clean atmosphere such as a clean room. The cleanliness is preferably class 1000 or less, more preferably class 100 or less, and still more preferably class 10 or less.

  As an example of the coating apparatus, FIG. 7 shows an example of the gravure coating apparatus 124, but the present invention is not limited to this. For example, methods such as a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a micro gravure method, and an extrusion coating method can be used as appropriate. The conveyance speed of the film 12 is preferably 5 to 200 m / min. Moreover, it is preferable that the width | variety of the coating layer formed in the film 12 is 0.5-3m.

  The film 12 on which the coating layer containing the liquid crystal compound is formed is dried by an initial drying zone 130 provided immediately downstream. Further, a drying zone 132 is provided on the downstream side of the initial drying zone 130, and the coated layer of the dried film 12 is further dried. And the hardening zone 136 is provided in the downstream of the drying zone 132, and the application layer of the dried film 12 is hardened.

  In this case, it is preferable to provide an intermediate zone 134 that is controlled to be lower than either the temperature of the drying zone 132 or the temperature of the curing zone 136 between the drying zone 132 and the curing zone 136. When the coating layer is transported directly from the drying zone 132 to the curing zone 136 without the intermediate zone 134, the film 12 heated in the drying zone 132 and the low molecular weight compound evaporated from the coating layer have a temperature higher than the drying zone 132. Condensation may occur in the low cure zone 136. Deposits (condensate) deposited by condensation adhere to and contaminate the back surface of the film 12 and the coating layer surface. Further, dew condensation on the wall surface of the curing zone 136 falls and adheres to the back surface of the belt-like film 12 and the coating film surface and is contaminated. Here, the low molecular weight compound means a compound having a molecular weight of 1000 or less.

  In the production of the optical compensation film, examples of the low molecular weight compound include triphenyl phosphate (TPP) and biphenyl diphenyl phosphate (BPP) as plasticizers, and Irgacure 184 and silane coupling as hardeners. Examples of the agent include acryloyloxypropyltrimethoxysilane.

  Then, the optical compensation film 13 manufactured through the curing zone 136 is taken up by the turret type film take-up device 10 through the take-up tension control device 138 and the film rewind device 16 described above. Reference numeral 138A denotes a dancer roller.

  In this way, the turret type film winding device 10 of the present invention is used for both winding of the film 12 and winding of the optical compensation film 13 manufactured by performing processing such as coating and drying on the film 12. By doing so, winding misalignment, winding wrinkles, scratches (including micro scratches of about 50μ ~ 100μ), film deformation at the center of the film, deformation of the film edge (commonly called ear) ) And other optical films having a high level of surface performance without winding failure.

  Next, various materials used for manufacturing the optical film of the present embodiment will be described.

  As the discotic compound (liquid crystal compound) used in the present embodiment, those described in JP-A-7-267902, JP-A-7-281028, and JP-A-7-306317 can be used. According to these, the optically anisotropic layer (coating layer containing a liquid crystalline compound) is a layer formed from a compound having a discotic structural unit. That is, the optically anisotropic layer is a polymer layer obtained by polymerization (curing) of a low molecular weight liquid crystal discotic compound layer such as a monomer or a polymerizable liquid crystal discotic compound.

  Examples of discotic (discotic) compounds include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physicslett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), such as azacrown and phenylacetylene macrocycles.

  The above discotic (discotic) compounds generally have a structure in which these are used as a mother nucleus at the center of a molecule, and a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, etc. are radially substituted as the linear chain. , Which shows liquid crystallinity and is generally called a discotic liquid crystal. However, the molecule itself is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. In addition, in the above publication, the term “formed from a discotic compound” does not require that the final product be the compound, for example, the low molecular discotic liquid crystal has a group that reacts with heat, light, or the like. As a result, it may be polymerized or cross-linked by reaction with heat, light, etc., to have a high molecular weight and lose liquid crystallinity. Furthermore, it is preferable to use a compound containing at least one discotic compound capable of forming a discotic nematic phase or a uniaxial columnar phase and having optical anisotropy. The discotic compound is preferably a triphenylene derivative. Here, the triphenylene derivative is preferably a compound represented by (Chemical Formula 2) described in JP-A-7-306317.

  A cellulose acylate film such as TAC is preferably used as the film 12 serving as a support for the alignment layer. Specifically, those described in detail in JP-A-9-152509 can be used. That is, the alignment film is provided on the cellulose acylate film or on an undercoat layer coated on the cellulose acylate film. The alignment film functions to define the alignment direction of the liquid crystalline discotic compound provided thereon. Here, the alignment film may be any layer as long as it can impart orientation to the optically anisotropic layer.

  Preferred examples of the alignment film include a layer subjected to a rubbing treatment of an organic compound (preferably a polymer), an oblique deposition layer of an inorganic compound, and a layer having a microgroove, and ω-tricosanoic acid, dioctadecylmethylammonium chloride and stearyl. Examples thereof include a cumulative film formed by Langmuir-Blodgett method (LB film) such as methyl acid, or a layer in which a dielectric is oriented by applying an electric field or a magnetic field.

  Examples of the organic compound for the alignment film include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, polyvinyl alcohol, poly (N-methylolacrylamide), and styrene / vinyltoluene copolymer. , Polymers such as chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl cellulose, polyethylene, polypropylene and polycarbonate, and Examples of the compound include a silane coupling agent. Examples of preferable polymers include polyimide, polystyrene, polymers of styrene derivatives, gelatin, polyvinyl alcohol, and alkyl-modified polyvinyl alcohol having an alkyl group (preferably having 6 or more carbon atoms).

  Among them, alkyl-modified polyvinyl alcohol is particularly preferable and has an excellent ability to uniformly align a liquid crystal discotic compound. This is presumably because of the strong interaction between the alkyl chain on the alignment film surface and the alkyl side chain of the discotic liquid crystal. In addition, the alkyl group preferably has 6 to 14 carbon atoms, and is further bonded to polyvinyl alcohol via -S-,-(CH3) C (CN)-or-(C2H5) N-CS-S-. Preferably it is. The alkyl-modified polyvinyl alcohol has an alkyl group at the end, and preferably has a saponification degree of 80% or more and a polymerization degree of 200 or more. Moreover, the polyvinyl alcohol which has an alkyl group in the said side chain can utilize commercial items, such as Kuraray Co., Ltd. product MP103, MP203, R1130.

  A polyimide film (preferably a fluorine atom-containing polyimide) widely used as an alignment film of a liquid crystal display (LCD) is also preferable as the organic alignment film. This is done by applying polyamic acid (for example, LQ / LX series manufactured by Hitachi Chemical Co., Ltd., SE series manufactured by Nissan Chemical Co., Ltd.) to the web surface and baking at 100 to 300 ° C. for 0.5 to 1 hour. And then obtained by rubbing.

  Furthermore, the alignment film applied to the cellulose acylate film is cured by introducing a reactive group into the polymer or using the polymer together with a crosslinking agent such as an isocyanate compound and an epoxy compound. It is preferable that it is a cured film obtained by this.

  It is preferable that the polymer used for the alignment film and the liquid crystalline compound of the optically anisotropic layer are chemically bonded via the interface between these layers. The polymer of the alignment film is preferably formed from polyvinyl alcohol in which at least one hydroxyl group is substituted with a group having a vinyl part, an oxiranyl part or an aziridinyl part. A group having a vinyl moiety, an oxiranyl moiety or an aziridinyl moiety is preferably bonded to the polymer chain of the polyvinyl alcohol derivative via an ether bond, a urethane bond, an acetal bond or an ester bond. It is preferred that the group having a vinyl moiety, an oxiranyl moiety or an aziridinyl moiety does not have an aromatic ring. The polyvinyl alcohol is preferably (Chemical Formula 22) described in JP-A-9-152509.

  For the rubbing treatment, a treatment method widely used as a liquid crystal alignment treatment process of the LCD can be used. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are flocked on average.

  Moreover, as a vapor deposition material of the inorganic oblique vapor deposition film, SiO is representative, and metal oxides such as TiO 2 and ZnO 2, fluorides such as MgF 2, and metals such as Au and Al are exemplified. The metal oxide can be used as an oblique deposition material as long as it has a high dielectric constant, and is not limited to the above. The inorganic oblique deposition film can be formed using a deposition apparatus. An inorganic oblique vapor deposition film can be formed by performing vapor deposition with the web fixed or by moving the long web to perform continuous vapor deposition. Examples of a method for aligning an optical anisotropic layer without using an alignment film include a method of applying an electric field or a magnetic field while heating the optical anisotropic layer on the web to a temperature at which a discotic liquid crystal layer can be formed. .

  As an application method of an optical compensation film having an optically anisotropic layer formed on a cellulose acylate film to a liquid crystal display device, the optical compensation film is bonded to one side of a polarizing plate via an adhesive, or a polarizing element It is preferable that the optical compensation film is bonded to one side of the film with an adhesive as a protective film. The optically anisotropic element preferably has at least a discotic structural unit (preferably a discotic liquid crystal).

  The disc surface of the discotic structural unit is inclined with respect to the cellulose acylate film surface, and the angle formed by the disc surface of the discotic structural unit and the cellulose acylate film is the depth direction of the optical anisotropic layer. It is preferable that it changes in.

  The optical compensation film is particularly preferably used for a transmissive liquid crystal display device. The transmissive liquid crystal display device includes a liquid crystal cell and two polarizing plates disposed on both sides thereof. The liquid crystal cell carries a liquid crystal between two electrode substrates. One optical compensation film is disposed between the liquid crystal cell and one polarizing plate, or two optical compensation films are disposed between the liquid crystal cell and both polarizing plates. The mode of the liquid crystal cell is preferably a VA mode, a TN mode, or an OCB mode.

  With a turret type film winding device, a 2000 mm wide and 80 μm thick triacetyl cellulose film formed on the film forming line of FIG. 1 is wound around 4000 m on the winding shaft, and the turret is swung when 3800 m is wound. The film was rewinded.

  And the quality of the winding film when the film was wound up on the winding conditions of the following experiments 1-3 was investigated.

(Winding condition)
Experiment 1 is a conventional film winding device that eliminates the entrained air that is wound into the winding roll by increasing the film winding tension without air press, and is 550 (N) both before and after turning the turret. The winding tension was used.

  Experiment 2 ... This is a method of excluding entrained air by air press. However, since the air nozzle is not integrated with the turret, it is necessary to retract the air nozzle out of the turning track when turning the turret. It is the conventional film winding apparatus which excludes accompanying air. That is, the winding tension before turning the turret was set to 400 (N), and the winding tension after turning was increased to 550 (N). The air press pressure before turning the turret was 8.0 (kPa), but after turning, the pressure was 0.0 (kPa) in order to retract the air nozzle.

  Experiment 3 ... This is a system that excludes entrained air by air press, and the film winding device of the present invention can perform air press both before and after turning of the turret by providing an air ejection unit integrally with the turret. It is. That is, the winding tension was 400 (N) both before and after the turret was swung, and the air press pressure was 8.0 (kPa).

(Quality evaluation method for winding film)
About each film wound up by the winding conditions of the said experiment 1, 2, 3, the winding quality was evaluated. As a winding evaluation method, two items of “winding deviation” and “black belt” were visually evaluated for the entire winding roll. Further, the winding of the turret before turning (winding roll up to a winding length of 3800 m, hereinafter referred to as the inner peripheral side) and after turning (up to the winding length of 3800 to 4000 m, hereinafter referred to as the outer peripheral side). For each of these, four items of “turtle beco”, “square winding”, and “ear beco” were visually evaluated.

(Evaluation criteria for evaluation items)
<Winding deviation> The degree of alignment and disorder of the end face (side surface) of the winding roll were evaluated at three levels of ○, Δ, and ×.

    O: The amount of deviation of the winding roll end face (difference between the maximum convexity and the maximum concaveness) is less than 3 mm, and the winding shape is beautiful.

    Δ: The amount of deviation of the winding roll end face (difference between the maximum convexity and the maximum concaveness) is 3 mm to 10 mm, and winding deviation is observed.

    X: The amount of deviation of the winding roll end face (difference between the maximum convexity and the maximum concaveness) exceeds 10 mm, and the winding shape is poor.

  <Black belt> This is also called blocking, and refers to a winding failure in which the film layers in the winding roll are brought into close contact with each other, and a portion having a transparent appearance appears due to the films sticking to each other. This is aggravated when the stress in the winding radial direction is too large, and occurs when the winding is too hard because there is no air trapped in the winding roll. Black belt failures were also evaluated at three levels, ◯, Δ, and ×.

    ○: No black belt is generated anywhere on the surface of the winding roll.

    Δ: A black belt is formed on a part of the surface of the winding roll.

    X: A black belt is generated in substantially the entire surface of the winding roll.

  <Turtle Beco> This is a winding failure in which a bevel deformation that looks like a turtle shell pattern occurs on the surface of the winding roll, and the entrained air trapped in the winding roll escapes over time, causing the surface of the winding roll to sink. Caused by Tortoise failure was also evaluated at three levels: ○, Δ, and ×.

    ○: No turtle bevel is generated anywhere on the surface of the winding roll.

    Δ: Weak turtles are formed on a part of the surface of the winding roll.

    X: Strong tortoise beaks are generated in a wide area on the surface of the winding roll.

  <Square winding> A winding failure in which the section of the winding roll in the radial direction did not have a beautiful circular shape and an angular deformation portion was observed in some places, and was evaluated at three levels of ○, Δ, and ×.

    ○: The winding roll has a beautiful circular cross section in the radial direction, and no square winding occurs.

    Δ: Weak angular winding occurs in part of the radial cross section of the winding roll.

    X: Strong angular winding occurs in a wide range of the radial cross section of the winding roll.

  <Ear extension> Also called “ear bevel”, it refers to a winding failure in which the knurled vicinity of both ends in the film width direction becomes wavy. When the winding tension is too high, it easily occurs, and the evaluation was made at three levels of ○, Δ, and ×.

    ○ ... Ear elongation does not occur at both ends of the surface of the winding roll.

    Δ: Weak ear elongation occurs at both ends of the winding roll surface.

X: Strong ear elongation occurs at both ends of the surface of the winding roll.
(Test results)
As a result, in Experiment 1 using the conventional film winding device, “winding deviation” and “black belt” of the winding roll were evaluated as “good”. However, “Kamebeko”, “Square winding”, and “Ear extension” on the inner peripheral side of the winding roll were all evaluated as Δ, and the outer peripheral side was evaluated as ×.

  Further, in Experiment 2 using a conventional air press type film winding device, the “roll misalignment” of the winding roll was evaluated as Δ, and the “black belt” was evaluated as ○. In addition, “Kamebeko”, “Square winding” and “Ear extension” on the inner peripheral side of the winding roll were all evaluated as “Good”. However, on the outer peripheral side of the winding roll that copes with the exclusion of entrained air by raising the winding tension without performing air press, “Kamebeko” and “Square winding” are evaluated as ×, and “Ear extension” is △ It was evaluation of.

  On the other hand, in Experiment 3 using the air press type film winding device of the present invention, the evaluation of “winding deviation” and “black belt” of the winding roll was good. Furthermore, “Kamebeko”, “Square winding”, and “Ear extension” were all evaluated as “good” on both the inner peripheral side and the outer peripheral side of the winding roll.

  DESCRIPTION OF SYMBOLS 10 ... Film winding apparatus, 12 ... Film, 14 ... Film production line, 16 ... Film rewinding apparatus, 18 ... Controller, 20 ... Mount, 22 ... Turret, 24 ... Air ejection unit, 26 ... Swirling axis, 28 ... Arm Plate, 30 ... Boss, 32 ... Winding shaft, 32A ... First winding shaft, 32B ... Second winding shaft, 34 ... Winding roll, 36 ... Air nozzle, 36A ... Air outlet, 38 ... Air introduction line, 38A ... Air intake, 38B ... Flexible hose, 38C ... Header pipe, 38D ... Rotary joint, 40 ... Moving means, 42 ... Air piping, 44 ... LM rail, 46 ... LM block

Claims (12)

A film winding process for winding an optical film with a winding device,
The winding device
A winding roll is formed by winding a traveling belt-like film on a winding shaft for 3800 m or more to form a winding roll, and turning a turret provided with a plurality of winding shafts around a turning shaft. A turret-type device that moves the take-up shaft to the take-up position.
An air nozzle that performs air pressing by blowing air having a pressure of 5 to 30 kPa to the surface of the winding roll;
An air introduction line for forming the swivel shaft hollow and introducing air into the air nozzle through the swivel shaft;
Moving means for moving the air nozzle following a change in the winding diameter of the winding roll while maintaining a predetermined distance between the air nozzle outlet and the winding roll surface;
An optical film characterized in that an air ejection unit including at least an air ejection unit is provided integrally with the turret for each winding shaft, and the air ejection unit is configured to rotate together with the rotation of the turret. Manufacturing method . The method of manufacturing an optical film according to claim 1, wherein the air ejection unit is disposed in a turning trajectory of the turret. 3. The optical film according to claim 1, wherein the rotary shaft is provided with a rotary joint that rotatably connects an air pipe to an air source provided outside the turret . Manufacturing method . A guide roller is provided that wraps the film wound around the winding roll by turning together with the turret when the turret is turned, and the air ejection unit is disposed in a travel path of the film wrapped by the guide roller. The method for producing an optical film according to any one of claims 1 to 3. 5. The support arm according to claim 4, wherein a support arm extends in a curved shape outside the flexible hose of the air introduction line, and a plurality of the guide rollers are rotatably supported by the support arm. Manufacturing method of optical film . Said moving means, optics according to any one of claims 1 to 5 in which the distance between the outlet and the winding roll surface of the air nozzle is characterized by moving the air nozzle while maintaining 2~15mm A method for producing a film . The air introduction line is branched from the pivot shaft to a header pipe provided for each air nozzle, and the air is uniformly introduced from the header pipe through a plurality of flexible hoses in the width direction of the air nozzle. The manufacturing method of the optical film of any one of Claims 1-6 characterized by the above-mentioned. Wherein each header pipes, optics according to any one of claims 1 to 7, it is characterized in that the pivot axis is capable of switching means switching within 3 seconds to switch the air it is provided to each air nozzle A method for producing a film . The moving means, as the dust of the drive unit is not-dropped onto the film, optics according to any one of the preceding claims, characterized in that it is provided a pair at both ends position of the air nozzle width direction A method for producing a film . The optical film manufacturing method according to claim 1 , wherein a cover is provided on the driving unit of the moving unit. The method for producing an optical film according to claim 1 , wherein the film has a width of 2000 mm or more. The method for producing an optical film according to claim 1, wherein the optical film is any one of a polarizing plate protective film, an optical compensation film, and an antireflection film for a liquid crystal display device.

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